The synthesis and anion binding properties of a fluorescent tripodal n-dansylamide (2) and a redox active tripodal quinone-based (3) receptor derived from 1,3,5-tris-(aminomethyl)-2,4,6-triethylbenzene. Herein the investigation of anion binding by these receptors via 1H-NMR, FT-IR, UV-Visible, and (APCI-MS) is reported. Fluorescence and electrochemical studies determined the ability of these receptors to sense anions. The downfield chemical shift changes in the 1H-NMR spectra and the low energy shifts of the νN-H stretching frequency in the FT-IR spectra indicated anion binding via hydrogen bonding. The binding constants for anion-receptor complex formation were determined and indicate a preference of receptor 2 for the binding of nitrate over chloride, bromide and iodide, while receptor 3 was also found to be selective for binding nitrate over chloride. For receptor 2, the 1:1 anion-receptor binding stoichiometry was confirmed by fluorescence Job plots and the 1:1 anion-receptor supramolecular complexes were identified by APCI-MS.
